
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ PI s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) t_0)) t_0))
1.0)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ PI s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) t_0)) t_0))
1.0)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
(FPCore (u s)
:precision binary32
(*
s
(-
(log
(+
(/
1.0
(+
(/ u (+ 1.0 (exp (/ (- PI) s))))
(/ (- 1.0 u) (+ 1.0 (exp (/ 1.0 (/ s PI)))))))
-1.0)))))
float code(float u, float s) {
return s * -logf(((1.0f / ((u / (1.0f + expf((-((float) M_PI) / s)))) + ((1.0f - u) / (1.0f + expf((1.0f / (s / ((float) M_PI)))))))) + -1.0f));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(1.0) / Float32(s / Float32(pi)))))))) + Float32(-1.0))))) end
function tmp = code(u, s) tmp = s * -log(((single(1.0) / ((u / (single(1.0) + exp((-single(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(1.0) / (s / single(pi)))))))) + single(-1.0))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(\frac{1}{\frac{u}{1 + e^{\frac{-\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{1}{\frac{s}{\pi}}}}} + -1\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
clear-num99.0%
inv-pow99.0%
Applied egg-rr99.0%
unpow-199.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
s
(-
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (/ (- PI) s))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s)))))))))))
float code(float u, float s) {
return s * -logf((-1.0f + (1.0f / ((u / (1.0f + expf((-((float) M_PI) / s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s))))))));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))))))))) end
function tmp = code(u, s) tmp = s * -log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + exp((-single(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))))))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(-1 + \frac{1}{\frac{u}{1 + e^{\frac{-\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s) :precision binary32 (* (- s) (log (fma -4.0 (/ (+ (* 0.5 (* u PI)) (* PI -0.25)) s) 1.0))))
float code(float u, float s) {
return -s * logf(fmaf(-4.0f, (((0.5f * (u * ((float) M_PI))) + (((float) M_PI) * -0.25f)) / s), 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(fma(Float32(-4.0), Float32(Float32(Float32(Float32(0.5) * Float32(u * Float32(pi))) + Float32(Float32(pi) * Float32(-0.25))) / s), Float32(1.0)))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\mathsf{fma}\left(-4, \frac{0.5 \cdot \left(u \cdot \pi\right) + \pi \cdot -0.25}{s}, 1\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 25.1%
+-commutative25.1%
fma-define25.1%
Simplified25.1%
Final simplification25.1%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
1.0
(* 4.0 (/ (- (* -0.25 (* u PI)) (+ (* PI -0.25) (* (* u PI) 0.25))) s))))))
float code(float u, float s) {
return -s * logf((1.0f + (4.0f * (((-0.25f * (u * ((float) M_PI))) - ((((float) M_PI) * -0.25f) + ((u * ((float) M_PI)) * 0.25f))) / s))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) + Float32(Float32(4.0) * Float32(Float32(Float32(Float32(-0.25) * Float32(u * Float32(pi))) - Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(u * Float32(pi)) * Float32(0.25)))) / s))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + (single(4.0) * (((single(-0.25) * (u * single(pi))) - ((single(pi) * single(-0.25)) + ((u * single(pi)) * single(0.25)))) / s)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + 4 \cdot \frac{-0.25 \cdot \left(u \cdot \pi\right) - \left(\pi \cdot -0.25 + \left(u \cdot \pi\right) \cdot 0.25\right)}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf 25.1%
Final simplification25.1%
(FPCore (u s) :precision binary32 (* (/ (pow s 2.0) (- s)) (* -4.0 (/ (+ (* 0.5 (* u PI)) (* PI -0.25)) s))))
float code(float u, float s) {
return (powf(s, 2.0f) / -s) * (-4.0f * (((0.5f * (u * ((float) M_PI))) + (((float) M_PI) * -0.25f)) / s));
}
function code(u, s) return Float32(Float32((s ^ Float32(2.0)) / Float32(-s)) * Float32(Float32(-4.0) * Float32(Float32(Float32(Float32(0.5) * Float32(u * Float32(pi))) + Float32(Float32(pi) * Float32(-0.25))) / s))) end
function tmp = code(u, s) tmp = ((s ^ single(2.0)) / -s) * (single(-4.0) * (((single(0.5) * (u * single(pi))) + (single(pi) * single(-0.25))) / s)); end
\begin{array}{l}
\\
\frac{{s}^{2}}{-s} \cdot \left(-4 \cdot \frac{0.5 \cdot \left(u \cdot \pi\right) + \pi \cdot -0.25}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.9%
associate--r+11.9%
cancel-sign-sub-inv11.9%
distribute-rgt-out--11.9%
*-commutative11.9%
metadata-eval11.9%
metadata-eval11.9%
*-commutative11.9%
Simplified11.9%
neg-sub011.9%
flip--14.5%
metadata-eval14.5%
pow214.5%
add-sqr-sqrt14.5%
sqrt-unprod9.0%
sqr-neg9.0%
sqrt-unprod-0.0%
add-sqr-sqrt7.7%
sub-neg7.7%
neg-sub07.7%
add-sqr-sqrt-0.0%
sqrt-unprod9.0%
sqr-neg9.0%
sqrt-unprod14.5%
add-sqr-sqrt14.5%
Applied egg-rr14.5%
sub0-neg14.5%
Simplified14.5%
Final simplification14.5%
(FPCore (u s) :precision binary32 (* (+ -1.0 (- 1.0 s)) (* 4.0 (/ (+ (* PI (+ 0.25 (* u -0.25))) (* PI (* u -0.25))) s))))
float code(float u, float s) {
return (-1.0f + (1.0f - s)) * (4.0f * (((((float) M_PI) * (0.25f + (u * -0.25f))) + (((float) M_PI) * (u * -0.25f))) / s));
}
function code(u, s) return Float32(Float32(Float32(-1.0) + Float32(Float32(1.0) - s)) * Float32(Float32(4.0) * Float32(Float32(Float32(Float32(pi) * Float32(Float32(0.25) + Float32(u * Float32(-0.25)))) + Float32(Float32(pi) * Float32(u * Float32(-0.25)))) / s))) end
function tmp = code(u, s) tmp = (single(-1.0) + (single(1.0) - s)) * (single(4.0) * (((single(pi) * (single(0.25) + (u * single(-0.25)))) + (single(pi) * (u * single(-0.25)))) / s)); end
\begin{array}{l}
\\
\left(-1 + \left(1 - s\right)\right) \cdot \left(4 \cdot \frac{\pi \cdot \left(0.25 + u \cdot -0.25\right) + \pi \cdot \left(u \cdot -0.25\right)}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
add-sqr-sqrt97.8%
distribute-rgt-neg-in97.8%
Applied egg-rr97.8%
distribute-rgt-neg-out97.8%
add-sqr-sqrt99.0%
expm1-log1p-u99.0%
expm1-undefine24.5%
Applied egg-rr24.5%
sub-neg24.5%
log1p-undefine24.5%
rem-exp-log24.5%
unsub-neg24.5%
metadata-eval24.5%
Simplified24.5%
Taylor expanded in s around -inf 13.5%
associate--r+13.5%
cancel-sign-sub-inv13.5%
cancel-sign-sub-inv13.5%
metadata-eval13.5%
associate-*r*13.5%
distribute-rgt-out13.5%
metadata-eval13.5%
*-commutative13.5%
*-commutative13.5%
associate-*l*13.5%
Simplified13.5%
Final simplification13.5%
(FPCore (u s) :precision binary32 (* (* -4.0 (/ (+ (* 0.5 (* u PI)) (* PI -0.25)) s)) (+ -1.0 (- 1.0 s))))
float code(float u, float s) {
return (-4.0f * (((0.5f * (u * ((float) M_PI))) + (((float) M_PI) * -0.25f)) / s)) * (-1.0f + (1.0f - s));
}
function code(u, s) return Float32(Float32(Float32(-4.0) * Float32(Float32(Float32(Float32(0.5) * Float32(u * Float32(pi))) + Float32(Float32(pi) * Float32(-0.25))) / s)) * Float32(Float32(-1.0) + Float32(Float32(1.0) - s))) end
function tmp = code(u, s) tmp = (single(-4.0) * (((single(0.5) * (u * single(pi))) + (single(pi) * single(-0.25))) / s)) * (single(-1.0) + (single(1.0) - s)); end
\begin{array}{l}
\\
\left(-4 \cdot \frac{0.5 \cdot \left(u \cdot \pi\right) + \pi \cdot -0.25}{s}\right) \cdot \left(-1 + \left(1 - s\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
add-sqr-sqrt97.8%
distribute-rgt-neg-in97.8%
Applied egg-rr97.8%
distribute-rgt-neg-out97.8%
add-sqr-sqrt99.0%
expm1-log1p-u99.0%
expm1-undefine24.5%
Applied egg-rr24.5%
sub-neg24.5%
log1p-undefine24.5%
rem-exp-log24.5%
unsub-neg24.5%
metadata-eval24.5%
Simplified24.5%
Taylor expanded in s around inf 13.5%
associate--r+11.9%
cancel-sign-sub-inv11.9%
distribute-rgt-out--11.9%
*-commutative11.9%
metadata-eval11.9%
metadata-eval11.9%
*-commutative11.9%
Simplified13.5%
Final simplification13.5%
(FPCore (u s) :precision binary32 (* (/ PI s) (+ -1.0 (- 1.0 s))))
float code(float u, float s) {
return (((float) M_PI) / s) * (-1.0f + (1.0f - s));
}
function code(u, s) return Float32(Float32(Float32(pi) / s) * Float32(Float32(-1.0) + Float32(Float32(1.0) - s))) end
function tmp = code(u, s) tmp = (single(pi) / s) * (single(-1.0) + (single(1.0) - s)); end
\begin{array}{l}
\\
\frac{\pi}{s} \cdot \left(-1 + \left(1 - s\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
add-sqr-sqrt97.8%
distribute-rgt-neg-in97.8%
Applied egg-rr97.8%
distribute-rgt-neg-out97.8%
add-sqr-sqrt99.0%
expm1-log1p-u99.0%
expm1-undefine24.5%
Applied egg-rr24.5%
sub-neg24.5%
log1p-undefine24.5%
rem-exp-log24.5%
unsub-neg24.5%
metadata-eval24.5%
Simplified24.5%
Taylor expanded in u around 0 13.4%
Final simplification13.4%
(FPCore (u s) :precision binary32 (* PI (+ -1.0 (* u 2.0))))
float code(float u, float s) {
return ((float) M_PI) * (-1.0f + (u * 2.0f));
}
function code(u, s) return Float32(Float32(pi) * Float32(Float32(-1.0) + Float32(u * Float32(2.0)))) end
function tmp = code(u, s) tmp = single(pi) * (single(-1.0) + (u * single(2.0))); end
\begin{array}{l}
\\
\pi \cdot \left(-1 + u \cdot 2\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.9%
associate--r+11.9%
cancel-sign-sub-inv11.9%
distribute-rgt-out--11.9%
*-commutative11.9%
metadata-eval11.9%
metadata-eval11.9%
*-commutative11.9%
Simplified11.9%
Taylor expanded in u around 0 11.9%
associate-*r*11.9%
distribute-rgt-out11.9%
Simplified11.9%
Final simplification11.9%
(FPCore (u s) :precision binary32 (- PI))
float code(float u, float s) {
return -((float) M_PI);
}
function code(u, s) return Float32(-Float32(pi)) end
function tmp = code(u, s) tmp = -single(pi); end
\begin{array}{l}
\\
-\pi
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0 11.6%
neg-mul-111.6%
Simplified11.6%
(FPCore (u s) :precision binary32 0.0)
float code(float u, float s) {
return 0.0f;
}
real(4) function code(u, s)
real(4), intent (in) :: u
real(4), intent (in) :: s
code = 0.0e0
end function
function code(u, s) return Float32(0.0) end
function tmp = code(u, s) tmp = single(0.0); end
\begin{array}{l}
\\
0
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 10.3%
Taylor expanded in s around 0 10.3%
herbie shell --seed 2024136
(FPCore (u s)
:name "Sample trimmed logistic on [-pi, pi]"
:precision binary32
:pre (and (and (<= 2.328306437e-10 u) (<= u 1.0)) (and (<= 0.0 s) (<= s 1.0651631)))
(* (- s) (log (- (/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) 1.0))))